348
FXUS65 KBYZ 072318
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
518 PM MDT WED OCT 7 2026
KEY MESSAGES
- VERY WARM, DRY AND OCCASIONALLY BREEZY THROUGH FRIDAY. FIRE
CONCERNS WILL REMAIN ELEVATED, AND MAY BE CRITICAL ON FRIDAY
WITH INCREASED WINDS AND LOWER HUMIDITIES.
- COLD FRONT ARRIVES EARLY SATURDAY, THEN MUCH COOLER SATURDAY
NIGHT THROUGH TUESDAY; THIS WILL BE THE COOLEST AIR MASS YET OF
THE FALL.
- STRONG WEATHER SYSTEM ARRIVES THIS WEEKEND. INCREASING
CONFIDENCE FOR MOUNTAINS/FOOTHILLS SNOW SATURDAY NIGHT TO
MONDAY, WITH RAIN AND WET SNOW AT LOWER ELEVATIONS. GREATEST
POTENTIAL FOR SNOW ACCUMULATIONS IS OVER MOUNTAINS AND FOOTHILLS
WEST OF BILLINGS. POTENTIAL IMPACTS TO TRAVEL AND OUTDOOR
RECREATION. DETAILS REMAIN VERY UNCERTAIN.
UPDATE
TAKING A CLOSER LOOK AT FIRE CONCERNS ON FRIDAY, HAVE OPTED TO ADD
FIRE ZONES 126 (BEARTOOTH RD), 274 (SHERIDAN CO) AND 284 (BIGHORN
NF) TO THE FIRE WEATHER WATCH. THESE SOUTHERN FOOTHILLS AREAS DID
NOT SEE THE SIGNIFICANT PRECIP THAT OTHER LOCATIONS RECEIVED BACK
IN SEPTEMBER, AND DROUGHT INDICES REFLECT THIS. FRIDAY WILL BE
VERY HOT AND DRY WITH MIXED SW-W WINDS GUSTING TO 30 MPH IN THE
HIGHLIGHTED ZONES. JKL
DISCUSSION
THROUGH NEXT WEDNESDAY...
ZONAL UPPER LEVEL FLOW WILL CONTINUE THROUGH FRIDAY BRINGING MUCH
ABOVE AVERAGE TEMPERATURES AND DRY CONDITIONS. THIS WILL CULMINATE
FRIDAY WHEN TEMPERATURES ARE EXPECTED TO BE IN THE 80S F, RELATIVE
HUMIDITY VALUES IN THE SINGLE DIGITS TO TEENS, AND WIND GUSTS
IN THE 20S AND 30S MPH. ELEVATED TO CRITICAL FIRE WEATHER
CONDITIONS ARE EXPECTED FRIDAY, ESPECIALLY ALONG THE FOOTHILLS
WEST OF BILLINGS WHERE WIND GUSTS IN EXCESS OF 40 MPH ARE
POSSIBLE (60-80%).
A PATTERN CHANGE IS EXPECTED SATURDAY THROUGH EARLY NEXT WEEK WITH
COOLER AND WETTER CONDITIONS EXPECTED. THERE ARE A LOT OF
VARIABLES WITH THIS SYSTEM THAT, COMBINED WITH HOW FAR OUT IT IS
(3-5 DAYS), ARE MAKING THE FORECAST HIGHLY UNCERTAIN AT THIS TIME.
THESE VARIABLES INCLUDE A SPLITTING TROUGH OVER THE PACIFIC
NORTHWEST, WITH ONE DIVING SOUTH ALONG THE WEST COAST AND THE
OTHER MOVING EAST ALONG NORTHERN CONUS, AND HURRICANE RACHEL.
ANALYSIS OF DETERMINISTIC MODELS INDICATES THAT A LOW PRESSURE
SYSTEM ASSOCIATED WITH THE PACIFIC NORTHWEST TROUGH WILL SLIDE
EAST BRINGING A COLD FRONT AND THE INITIAL BATCH OF MOISTURE
SATURDAY. HURRICANE RACHEL THEN WEAKENS AND HEADS TOWARDS THE
CALIFORNIA COAST SUNDAY AND MONDAY, EVENTUALLY COMBINING WITH A
CUTOFF LOW. THIS WILL ACT TO ADVECT ADDITIONAL MOISTURE INTO
MONTANA SUNDAY AND MONDAY.
IT APPEARS THAT POTENTIAL PRECIPITATION AMOUNTS HAVE INCREASED
EAST OF BILLINGS DUE TO THIS ADDITIONAL MOISTURE BEING BROUGHT IN
BY RACHEL, THOUGH THE HIGHEST AMOUNTS ARE STILL EXPECTED FOR THE
MOUNTAINS AND FOOTHILLS. AREAS WEST OF A LINE FROM ROUNDUP TO
SHERIDAN HAVE A 70-90% CHANCE OF GETTING GREATER THAN 0.5 INCHES
OF PRECIPITATION, WITH AREAS TO THE EAST HAVING A 30-60% CHANCE.
PRECIPITATION TYPE IS EXPECTED TO BE MOSTLY SNOW FOR THE MOUNTAINS
AND FOOTHILLS AND A RAIN/SNOW MIX FOR THE REST OF THE REGION.
SIGNIFICANT UNCERTAINTY MAKES IT DIFFICULT TO PREDICT SNOW AMOUNTS
AT THIS TIME, BUT CONFIDENCE IS HIGH THAT THE ABSAROKA/BEARTOOTH
AND CRAZY MOUNTAINS WILL SEE THEIR FIRST HEAVY SNOW OF THE SEASON,
WITH THE FOOTHILLS WEST OF BILLINGS AND THE BIGHORN MOUNTAINS
SEEING AT LEAST LIGHT SNOW. WARMER TEMPERATURES AND WARM GROUND
SURFACES WILL MAKE ACCUMULATING SNOW MORE DIFFICULT FOR LOWER
ELEVATIONS, THOUGH EVEN THESE AREAS HAVE A 20-50% CHANCE OF
GETTING GREATER THAN 1 INCH. THIS PATTERN WILL LIKELY BRING THE
FIRST WIDESPREAD FROST OF THE SEASON SUNDAY AND MONDAY MORNINGS
AS HIGH TEMPERATURES THESE DAYS ARE ONLY EXPECTED TO BE IN THE 40S
F. TORGERSON
AVIATION
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. OTHERWISE,
OCCASIONAL BREEZY CONDITIONS WILL EXIST LATE TONIGHT OVER FAR
EASTERN MONTANA AND THURSDAY OVER SOUTH-CENTRAL MONTANA. LA
PRELIMINARY POINT TEMP/POPS
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 045/079 050/084 053/068 034/040 031/044 030/052 035/056
00/U 00/U 01/B 89/W 96/W 21/B 33/W
LVM 043/079 045/083 047/066 026/041 023/045 025/054 030/055
00/U 00/N 05/W 9+/W 94/W 22/W 34/W
HDN 040/079 045/087 050/071 033/043 031/047 028/055 031/057
00/U 00/U 00/B 78/W 86/W 21/B 34/W
MLS 044/074 048/084 051/070 037/044 034/045 032/054 037/057
00/U 00/B 00/B 68/W 86/W 21/B 34/W
4BQ 044/077 050/086 053/075 039/046 035/045 031/056 037/058
00/U 00/U 00/U 56/W 96/W 22/W 34/W
BHK 040/076 045/085 050/076 033/046 029/045 026/053 030/058
00/U 00/B 00/U 66/W 86/W 22/W 24/W
SHR 043/078 044/088 049/075 032/046 028/046 028/057 031/058
00/U 00/U 01/B 78/W 96/W 32/W 45/W
BYZ WATCHES/WARNINGS/ADVISORIES
MT...FIRE WEATHER WATCH IN EFFECT FRIDAY AFTERNOON FOR ZONE 117.
FIRE WEATHER WATCH IN EFFECT FROM FRIDAY AFTERNOON THROUGH
FRIDAY EVENING FOR ZONES 123-124-126.
WY...FIRE WEATHER WATCH IN EFFECT FROM FRIDAY AFTERNOON THROUGH
FRIDAY EVENING FOR ZONES 274-284.
WEATHER.GOV/BILLINGS
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